Asthma is a common disease and a significant public health problem, affecting one in every 10 individuals, nearly 30 million people in the US alone. About 5-10% of asthmatics have severe disease that is difficult to control with standard therapies. Severe asthmatics are considered to be relatively resistant to corticosteroids, a mainstay of therapy in asthma. Furthermore, chronic corticosteroid therapy often results in side effects that adversely affect outcomes. Thus, more effective treatment options, which are safe, cost-effective and easy to administer, are needed for severe asthmatics. A better understanding of the different factors that contribute to disease severity and pathogenesis will be necessary to identify new, personalized treatment and management approaches for severe asthmatics. Our goal is to gain a better understanding of the pathogenic mechanisms that differentiate severe asthma from mild to moderate asthma. In so doing, we hope to discover novel pathways that can be targeted to achieve our primary aim of developing new therapies for severe asthmatics. Progress achieved under this protocol is summarized as follows: 1. Serum levels of apolipoprotein A-I and large High Density Lipoprotein particles have been shown to be positively correlated with FEV1 in patients with atopic asthma. This demonstrates that circulating HDL particles are associated with less severe airflow obstruction in allergic asthma. A manuscript describing these finding has been published in the American Journal of Respiratory and Critical Care Medicine. 2. Serum levels of high-density lipoproteins have been shown to be negatively correlated with biomarkers of type 2 inflammation (e.g., blood eosinophil counts and serum periostin levels) in atopic asthmatics. In atopic asthmatics, blood eosinophils negatively correlated with serum HDL-cholesterol and total HDL particles measured by NMR spectroscopy (HDLNMR). Serum periostin levels negatively correlated with total HDLNMR. In contrast, blood eosinophil counts positively correlated with serum triglyceride levels. This study demonstrates for the first time that HDL particles were negatively correlated, whereas serum triglycerides were positively correlated, with blood eosinophils in atopic asthmatics. This finding supports the concept that serum levels of HDL and triglycerides may be linked to systemic type 2 inflammation in atopic asthma.